Annealing.....things that don't like to be annealed.

[LehighBrad]

Say a fellow comes across a "cheapy" rough cast pistol guard that he buys for 3 bucks at the riflemaker's fair knowing it more than likely is made of a brass alloy mix. The question this fellow has is....will heating it with a torch anneal it enough to make it more "bendy"?? I've annealed PURE brass parts before, but never a brass alloy mix.    And I've learned from past builds that trying to cold bend a brass / alloy part is like bending a glass window pane.  

[bama]

I have only used the brass alloy once, once was enough, i could not seem to aneal it. I was just using a small propane tourch. This material is very hard and is hard on your files and drill bits. Give me good yellow brass anyday, it is a pleasure to work with.

[LehighBrad]

Yeah....I thought as much.    But for finding the trigger guard in a "clearance box" in Dixon's shop I figured if I snap it off trying to bend it to how I want it...no big loss. I am sort of kickin' myself in the a** now knowing I should've just ponied up the $35 bucks for the nicely cast pure brass one I seen at Chris Atland of York County Firelock's table.  Live and learn I guess.

[Hungry Horse]

Brad, you are heating this bronze alloy to red hot, and then quenching in cold water, aren't you? annealed this way it will be more likely to bend than break. A propane torch is unlikely to produce the BTU's required to get the guard uniformaly red hot. I've found these alloys tend to behave differently, depending on the metal mix. Of course you have no way of knowing what the mix is. Most are some form of red bronze.

    Hungry Horse

[T*O*F]

you are heating this bronze alloy to red hot

First of all, people start to make "assumptions" which may not be germaine to the item being discussed.

Is the part a sand casting?  If so, then they have been provided by suppliers for eons and used successfully by thousands of makers over the years.  Just because it isn't an investment casting of pure brass doesn't mean it's junk and therefore unusable.

IF it's a sand casting, work it down to a usable form.  Sand castings have a hard outer skin impregnated with silica sand and dust, which is why they are so hard to work initially and are prone to cracking.  You can't use them as they come from the mold.  Once you get rid of that shell and file out as many inclusions as possible, then it will be in a form that you can work with, at which point you can anneal it.  A this point, with reasonable care, you can bend it to conform to your needs.

There is an inherent form of bigotry which exists that only products from certain modern suppliers are suitable for building a gun and all others are junk.  This is mainly due to the fact that they require less prep work, which is a time saving feature, and time is money for the professional.  This bigotry over time becomes a form of elitism whereby new gunbuilders, asking for advice on forums,  come to believe that only certain parts should be used.  This mindset, based on opinion, is a poke o' hockey.

[jerrywh]

 There are a lot of different kinds of brass and there are metals that look like brass but are actually bronze. Bronze is an alloy of tin and copper. Brass is an alloy of zinc and copper. Also the composition of the alloy makes a lot of difference in how it is heat treated. Most brass will anneal well and  some brass will bend cold very well. Brass is a metal that is called by blacksmiths hot short.
 Brass will break or crumble if you try to bend it when heated [much].  Brass is annealed by heating it to 1350° or a little more and quenched.  Some parts that look like brass are actually silicone bronze. They will not anneal by any means I have found . I researched it a lot because I have cast both.  The very best brass is called 360 alloy in my opinion. It is about 70 percent copper and 30 percent zinc and is almost as flexible as silver. If it won't anneal it is probably bronze.
  It makes no difference if the metal is sand cast or precision cast the properties are essentially the same except the precision cast parts will have a much finer finish and usually have no inclusions. Sand casting is far inferior to lost wax casting. Believe me they don't sand cast jet engine parts.  The end product  represents the person or company  doing the casting. It's not the guitar that makes the music it's the hand holding the pick.

[bama]

There was a reason it was in the clearence ben, do what you will, say what you want, before it's over you will be wishing you had your 3 dollars back.

[T*O*F]

There was a reason it was in the clearence ben,

As a matter of fact, there are many reasons why parts end up in the clearance bin, the least of which is because it is a junk part.
1.  A clearance bin is a good marketing practice.  It gets people to stop at your booth where you can engage them in conversation which often leads to selling the individual other parts.
2.  You have old inventory which you want to move out to make room for stuff that will turn over faster.
3.  The parts may be of a type gun that no one builds anymore.
4.  Clearance parts allow the man with a small budget to build a gun he might not otherwise afford.
5.  He may have picked up a bunch of parts on a deal and is still making money by closing them out.
6.  People can't resist a bargain if it fits their needs.
I could go on and on.

[LehighBrad]

T*O*F.....you are correct....this 3 dollar trigger guard is exactly the type I was looking for....but as I said...if it would've been wax cast and much nicer...so would've the price. I got all the time in the world to work it down and make it look nice and clean, and if it so happens I can bend it enough to follow the curvature of my pistols grip, all the better! Who knows...it may be pure brass after all and was thrown in the bargain box because of its rough finish and flashing seams showing or no one else was looking for that particular pistol trigger guard before I found it.    And #6...I can't pass up bargain bin gun parts!  Thanks fellas for the replies. 

[Joe S.]

Too funny,three dollars?what do you want for three bucks?like the other guy said reasons why there's bargain bins.Sometimes you win sometimes not so much.

[Hungry Horse]

Brad; 

 In my experience, I rarely find sand castings in bronze alloys, they are usually yellow brass.

  Hungry Horse

[LehighBrad]

The pistol and its 3 dollar trigger guard....finished pistol pictures soon.    My neighbors curly maple tree provided the stock blank (in background)....after seeing the SUPREME figure in its grain I wish I would've asked him to save me a chunk long enough for a future longrifle too!!

[rich pierce]

Good buy.  Not sure why paying more would make it better. 

[Hungry Horse]

 I've got one of those trigger guards, it's yellow brass. I think I got it on a close out from TOTW years ago. They are very rough, with a big casting seam.

  Hungry Horse

[JCKelly]

A little redundant, but -

Brass is an alloy. Usually of copper and zinc, sometimes with a couple % of lead in it.

An alloy is a mix of two or more metals. So "pure brass' doesn't mean much.

One reason brass tends to crumble when heated is that a lot of brass has lead in it. In bar it is for improved machinability. For castings (except plumbing in California) it makes a sounder casting.
If you heat this brass the lead melts, by about 621F, and the liquid lead gets into the boundaries between the grains. So the whole thing has only the ductiliy of a chunk of melted lead, meaning Zero.

Investment, or Lost Wax, castings have beautiful surface finish & fine detail one cannot get in a sand castings.

When making an investment casting the molten brass is poured into a ceramic mould that is hot from the furnace used to burn out the wax. A hot mould also lets the molten metal flow better into all the fine crevices, for good detail.
It also means that the investment cast metal freezes rather slowly, which makes it coarse grained.  Outside of jet engine hot parts one would generally prefer a finer grain for better ductility and strength.

Sand castings have comparatively rough finish & less detail. They also cool faster, making a finer grained casting.

Look at old brass door handles on public buildings, which have been etched by generations of sweaty hands. You can see the grain pattern. You may also note that it is coarser in the thick parts of the handle and finer in the thin parts. Because the thick parts froze more slowly than the thin.

Investment cast steel parts have horribly coarse grains. The good news with steel, unlike brass, is these grains may be made fine again by annealing or normalizing (heat bright red & cool in air, for plain carbon steel) I personally do not know if any of the investment cast steel parts suppliers have their castings annealed after removing them from the mould.

[TMerkley]

Great thread!!!
I learned something new. 
Sometimes the people pay more just for the bragging rights of saying "mine is better!"
In this case, the three dollar part was just as good or better than the high-dollar part.  Now you can say "mine is better because I put forth the effort to make it better!"

[bgf]

Good buy.  Not sure why paying more would make it better. 

Apparently sand cast parts are not authentic to longrifles...! 

[LehighBrad]

All I can say is, after working with this trigger guard, I can safely say....if it ain't pure soft brass...it's dang close. BEST 3 bucks I've spent in a long time! Files down nicely..and is very malleable. So I guess good bargin finds CAN be had.   And thanks for that bit of info JCKelly.....I enjoy learning stuff like that!

[jerrywh]

 This may be of some interest.  In the colonies many of the gunsmiths cast their own brass parts. I will venture to say they were all sand cast. Probably some of the brass parts were imported from England or maybe even Germany. Any brass parts that were imported would have been cast by professionals who were in a guild. there is a lot of difference. A colonial  gunsmith probably would have mixed his own sand for casting but there were foundries in the colonies. In England the casters used a special sand. It was silver casters sand.  Silver casters sand was very fine and castings could be produced that was very near equal to precision casting of today. I have inspected some castings from different guns from Europe and England that show the exact same minor defects.  This indicates that the same mold was used and the castings were sold throughout the gun making community.  This silver casting sand can still be purchased today from some places in England. It is similar to what we call petrobond. http://www.ebay.com/itm/like/381190042640?lpid=82&chn=ps 
 The fact is wax casting has been dome for at least 3000 years. Even the south American Indians were wax casting gold.

[Chris Treichel]

If you want to get more heat focused on the part... get a few red bricks from the hardware store and arrange them so you have a covered U shape and place the part inside... now heat with the torch and it will focus more energy where you want it. Be careful not to melt the brass alloy whatever it may be. 

[John Archer]

Annealing brass is easily done with just a propane torch. You only need to take it to 800 degrees or so. It will get slightly softer if you take it higher. Watch the flame and when it gives off orange colors as it comes off the brass it's good. Quench if you must...I don't, just let it air cool.

John

[yulzari]

Brass certainly can be annealed as a visit to any brass pot and pan makers workshop in North Africa or India will demonstrate. The brass is hammered to stretch, shrink  and shape it and annealed as soon as it  is found to have work hardened. The brass they use is proper coper/zinc. No lead and not bronze with tin, although that is worked as a separate trade in the same way.

I suspect that some of the difficulty that people find bending castings is to treat it as if it were steel. Brass, like copper and bronze, work hardens. Grind/sand/file off the hard outer silica contaminated skin which will otherwise crack and propagate the crack into the inner brass. Then bend slightly. Anneal and bend some more. Work it is small stages annealing between each. Different proportions of copper to zinc will have different propensities to work harden but simply be patient and cautious even if it means that you anneal too often.

Another problem can be the base metal. In the 18th century the British Ordnance were requiring closer inspection of brasswork for muskets if they were made from scrap brass rather than virgin brass. If the caster used scrap then all sorts of small amounts of God knows what may have contaminated the brass alloy.

As trivia: lead worksoftens so sheet roofing lead can seem softer than when cast as it has been softened by rolling.

[jerrywh]

How did we get from annealing a trigger guard to rusted out cars?

[Ky-Flinter]

How did we get from annealing a trigger guard to rusted out cars?

I have removed the conversation about old rusty cars.  This forum is the AmericanLongRifles Gun Building Forum, not Car and Driver.  Please keep replies on the topic at hand.  Thank you.

-Ron

[yulzari]

How did we get from annealing a trigger guard to rusted out cars?

By referring to an example of the practical effects of contamination upon metal made from impure scrap. Relevant to the reference to closer examination of scrap remelt brass by the British Ordnance which reference itself demonstrates a possible cause of poor bending capacity of some brass.

I would refer you to the Doctoral thesis of De Witt Bailey Ph.D wherein he notes the necessity found for the closer monitoring as remelted scrap brass had been found to be more brittle than virgin brass. This was also a reason why (also economy) the Tower of London sent scrap brass gun furniture to it's contracted brass founders for new cast gun furniture as they knew the quality of the scrap brass thus going into the remelt.